My first post and a question on a long range sight for a model 78.
There is no tang on this rifle but I still want a sight that will let me get out to 300 to 400 meters using 550 gr. cast bullets.
Any suggestions?

You probably have 3 options: Use Williams FP-1885 receiver sight (I think it will elevate enough for your use, but I'm not positive), mount a tang sight to the wood stock, or have a gunsmith add a tang to your receiver. I guess one other option is to use an elevator sight in place of the rear U-notch sight (a sight that works like a regular U-notch or buckhorn sight when folded down, but which flips up for a long range aperture sight).